1. Field of the Invention
The present invention relates to a solid-state image pickup device, and particularly relates to a solid-state image pickup device used as a device provided to convert light into an electric signal and output an image signal, the solid-state image pickup device featuring the driver of an actuator which drives a lens fixed to the upper part of an imaging area of the solid-state image pickup device.
2. Description of the Related Art
FIG. 1 shows an exemplary configuration of an ordinary camera used in related art.
The camera used in related art includes a solid-state image pickup device (image sensor) 11, a lens 12, an actuator 13, a driver 14, and a control integrated circuit (IC) 15.
Usually, the solid-state image pickup device 11 is provided near the lens 12. Further, the actuator 13 provided to drive the lens 12 is provided near the solid-state image pickup device 11.
The solid-state image pickup device 11 is significantly sensitive to a noise. In the past, therefore, a noise emitted from a device or the like provided near the solid-state image pickup device 11 sneaked into the solid-state image pickup device 11. Consequently, image signals were deteriorated. Since noises emitted from the actuator 13 provided near the solid-state image pickup device 11 get into the solid-state image pickup device 11 as a matter of course, provisions for the noises emitted from the actuator 13 or the like provided near the solid-state image pickup device 11 should be made.
There are various types of actuators that can be used as the above-described actuator 13. For example, there are an actuator operating through pulse driving and an actuator operating through a direct current (DC) and/or a voltage. Hereinafter, the actuator 13 operating through the pulse driving will be referred to as a pulse-driven actuator 13.
Particularly, the pulse-driven actuator 13 performs an operation causing the instantaneous passage of a current. At the moment of the above-described operation, noises emitted from the power source, the ground (GND), and a signal line provided to transfer a pulse signal, and/or noises transmitted via various types of signal lines (the power source and the GND) sneak into the solid-state image pickup device 11 and deteriorate image signals.
Therefore, it is important that provisions be made for noises which may get into the solid-state image pickup device 11, the noises having been emitted from the pulse-driven actuator 13.
As the provisions made for the noises which may get into the solid-state image pickup device 11, there is a method of blocking paths through which the above-described noises may be transmitted. More specifically, there are provisions that prevent noises from getting into the solid-state image pickup device 11, as below. Namely, the solid-state image pickup device 11 may be separated from components including the actuator 13, the driver 14, and so forth that can be the noise source. Further, the power source may be separated from the GND. Still further, a capacitive component may be provided between the power source and the GND so that noises doe not sneak into the power source and/or the GND.
However, the above-described provisions made for blocking the paths through which the noises may be transmitted, that is, the provisions which allow for separating the components that can be the noise source from each other, providing the capacitive component, and so forth are not appropriate in the field where downsizing of a mobile-phone camera module or the like is demanded, since the components should be provided in wide space.
There are other provisions, such as those disclosed in Japanese Unexamined Patent Application Publication No. 2001-43302. According to the above-described provisions, driving the actuator 13 is stopped during the time period over which image signals are output so that the image deterioration is reduced. According to the above-described provisions, however, it becomes difficult to drive the actuator 13 while the image signals are output. In that case, the actuator 13 operates only in a blanking period. As a result, the operation speed of the actuator 13 is decreased so that the speed of focus control and/or zoom control performed through the lens 12 is decreased.